KEAP1 and cancer: Cancer cells, in order to reduce the overproduction of ROS and the related toxic effects while maintaining cell proliferation and survival conditions, can activate two major response mechanisms: the Kelch-like ECH-associated protein 1 (KEAP1)-nuclear factor erythroid 2-related factor 2 (Nrf2) (encoded by NFE2L2 gene) pathway and GSH metabolism [82].